My 99 Teg is still having some roaming/high idle issues.

I am now almost 100% sure it is due to IACV.

I just need to confirm a few things about IACV before I can be totally sure of this.

Please tell me if this is correct. The IACV is basically an valve that is always open except for when the car is at normal operating temps. The valve stays open while the car warms up to bring more air into the motor. The two coolant hoses run into the valve so that it can sense when these temps have been met so that it will can close itself after that.

The reason why IACV is usually the culprit of high idle is because as the valve gets dirty, the sticky stuff inside the manifold will force the valve open. This is why even after the car is at operating temps, the idle will be high..

The part I'm not sure is, then why does this also cause a roaming idle?
If the valve is stuck open, then would it not simply keep the idle high only?

I recently cleaned out the IACV and the roaming idle did go away, but the idle stayed high.
Today, as I was checking the coolant hoses connected to the IACV, the revs started roaming again and the idle was jumpy, but not like before. Before it would slowly roam from 1k-1.5k when idle... now it stays at 1.5k and roams to 1.6 to 1.7k very rapidly.. almost like the motor is about to die. Looking at the RPM needle, I could barley see it fluctuate, but it is definitely jumpy.

I'm not sure how this all of a sudden happened, but could anyone tell me how by simply touching the IACV coolant lines, that this would happen all of a sudden?

If I disconnect the IACV, the idle is nice and smooth and has no issues at all. SO this is why I think it's definitely the IACV.

My car is an automatic. With the IACV plugged in, the car idles high but not jumpy when shifted to drive or reverse. It only does this when in P mode.

 

its magic. just replace it.

 

You need to change the title of your thread....

Your car has an EACV, not an IACV.

Secondly, it would help to know exactly how you went about cleaning your EACV. If you disconnected the EACV from the manifold and the 2 coolant lines attached to it, you may now have a vacuum leak where the valve and manifold meet or maybe you need to bleed the air out of the cooling system and refill it to make up for what was lost when removed.

There's not many other ways to clean an EACV, but i wont assume you cleaned it by removing the piece all together. Who knows what your definition of cleaning an EACV is.

When did this roaming idle issue happen? Usually doesn't happen out of nowhere so was there some sort of adjustment made, parts changed, or occurance that may have led to this problem?

Worst case scenario, you somehow broke the EACV while handling it or was faulty in the first place and you need a new one.

 

ok nee some help i have researched and researched i have a 92 civic dx with a freshly rebuilt d15b7 when it starts up it idles rough and wont rev out seems to be cutting out. i re-timed it by the book three times so i know its right new distrubtor, wires and plugs both my stock p06 and a p28 ecu do this when hooked up. what else could it be map sensor tps sensor plz help!